This invention relates generally to apparatus for developing diazotype copy material and, more particularly, to means for guiding the copy sheet material safely through the developing apparatus.
The method of developing diazo copy material by the application of relatively small, metered quantities of liquid developer is described in U.S. Pat. No. 3,446,620 and assigned to the same assignee.
Apparatus for carrying out the above method is disclosed in U.S. Pat. Nos. 3,626,833, 3,640,203 and 3,704,662, also assigned to the same assignee.
A further method and apparatus for pressure-diazo reproduction is disclosed in copending application Ser. No. 837,742, filed Sept. 29, 1977, assigned to the same assignee. As disclosed therein, there is provided a pressure-diazo developer apparatus comprising a pair of applicator rollers positioned in axially spaced and parallel relation rotatably mounted in an enclosure. The dual rollers enhance the copy quality and permit high volume reproduction. Thus, in a single roller machine as in the prior art, interstices appear in the developed copy sheet caused by the grinding pattern of the roller surface and the texture of the copy paper. However, with dual rollers the second roller is effective to fill-in the interstices missed by the first roller, thereby producing a diazo copy of a quality considerably higher than that which can be produced with a single roller developer apparatus.
In direct contact copy machines, wherein a superimposed copy sheet and original tracing are exposed and subsequently separated, and the copy sheet is transported through a developing apparatus whereat a liquid developer is applied to the copy sheet as the latter is carried over one or more rotatable applicator rollers, there exists the possibility that the copy sheet, rather than merely passing over the rollers, will adhere to the wetted roller surface and become wrapped thereabout. If this occurs, the copy sheet could be damaged and it becomes a difficult and time consuming matter to easily release the wrapped copy sheet from the roller.
The principal advantage of the pressure-diazo apparatus disclosed in the above application is that the dual roller arrangement enables high volume reproduction and copies of a quality comparable to those of an ammonia diazo process. However, the apparatus does not provide for the prevention of copy sheet jamming during passage of the sheet through the developing apparatus. The present invention provides copy sheet guide means for use with, for example, a machine as described in the above application which prevents the copy sheets from adhering to the wetted rollers and causing a sheet jam.